Keyboard



FIG. 1 is a top view of a keyboard;

FIG. 2 is a top and left perspective view thereof;

FIG. 3 is a top and right perspective view thereof; and,

FIG. 4 is a magnified view of portion 4 of FIG. 1.

Any broken lines shown are included for the purpose of illustrating unclaimed portions and form no part of the claim. 

CLAIM The ornamental design for a keyboard, as shown and described. 